The ribbonlike leaves of ornamental grasses tend to catch our eye. From the lowliest clumps of blue-tinged sheep fescue to the variegated leaves of Japanese ribbon grass, gently rustling leaves give a perennial garden a certain wild and carefree quality that can be informal and inviting.

Ornamental grasses may be easy to grow, but are all grasses something we should tolerate – let alone invite – in our landscape?

Perhaps a striking stand of exotic-looking pampas grass has caught your eye while traveling about, particularly along the eastern seaboard. A large perennial grass native to South America and supposedly hardy only to Zone 6, the plant grows in enormous and continuously expanding clumps 8 to 10 feet high. In late summer silvery-white or pinkish silken plumes rise to a height of 12 feet. By this time of year, frost has killed the plant in most areas, turning the lush, green leaves to brown and leaving the huge, plumelike seed heads waving about in the breeze, dispersing seed and increasing the plant’s range.

There are many ornamental forms of pampas grass that seem to have an attractive and functional use in the landscape. Often it is used as a specimen plant in isolated locations on large lawns. It quickly grows into a massive stand, making it an effective screening plant in sunny locations.

Tolerant of high levels of salt in the soil, often large communities of various pampas grass species may seen along roadside areas. Some say the striking feathery plumes combined with large, graceful clumps of foliage make pampas grass a very interesting addition to the landscape. Others think quite differently. In some areas of the country, this grass is invasive and threatens the unique ecological integrity of coastal dunes and estuarine areas. Plants produce millions of seeds that develop without pollination. The grass is an aggressive colonizer that competes with native vegetation. It can displace native vegetation in ecologically sensitive areas and may even slow early forest regrowth on logged lands.

Getting rid of the plant once it’s established can be tricky. Its stems are enormous. They require cutting off with lopping shears or a chain saw.

Another plant often disrupts the balance of vegetation in the landscape. Yellow nutsedge is a perennial grass that reproduces primarily by small underground tubers called nutlets. The troublesome plant also can spread by rhizomes (below-ground stems) and may germinate from seed. Farmers have a great deal of difficulty controlling this plant when it is found as a weed among their crops. With the rising acreage of farmland subjected to residential sites, yellow nutsedge plants are often found in the soil of lawns.

Yellow nutsedge is most easily identified by the triangular shape of the stem. A thick vein runs down the middle of each blade, and each leaf has a very waxy covering. If one rolls the stem of the plant between the fingers, a triangular shape may be felt. The leaves are light green to yellowish in color and are very slick or waxy to the touch.

Nutsedge produces a shallow, fibrous root system, often with many nutlike tubers – underground food storage organs. Each of these tubers can germinate and produce new plants. Each new plant also can produce rhizomes which can give rise to additional new plants.

In the home lawn, a healthy, dense, vigorous stand of turf can compete with yellow nutsedge. Proper care of the lawn, therefore, is really is the best control method for the obnoxious plants. Regular mowing and proper fertilization and liming regimes based on soil testing recommendations is advised.

If only a few yellow nutsedge plants are present, hand pulling may be a successful way to eliminate the problem. Removal of the entire plant including root systems is necessary. Pulling mature plants is difficult. These plants will often break off at the soil surface allowing new growth from tubers below the soil line. Monitor the area several weeks after pulling the yellow nutsedge; pull any other plants that have grown from the underground nutlets stored in the soil.

Unlike most lawn weeds, yellow nutsedge is not controlled with applications of traditional annual grass weed or broadleaf weed control products. This weed is a member of the sedge family and requires the use of very specific herbicides to achieve satisfactory control. Eradication of large, mature plants from lawns is difficult, even with the help of a professional certified in the use of chemical weed control.

Diana George Chapin is the NEWS garden columnist. Send horticulture questions to Gardening Questions, 512 North Ridge Road, Montville 04941, or e-mail dianagc@midcoast.com. Selected questions will be answered in future columns. Include name, address and telephone number.